One of the above referenced Chance et al, U.S. Pat. No. 4,452,250 is entitled "NMR System for the Non-Invasive Study of Phosphorus Metabolism." This patent provides detailed electrical information relating to the basic construction of NMR apparatus suitable for employment in conjunction with apparatus of the present invention.
The other patent, Chance U.S. Pat. No. 4,441,502--, discloses NMR apparatus for determining the relationship between the work output rate of an exercising human body member and the steady-state capability of oxidative phosphorylation in a muscle responsible for the exercise. In the U.S. Pat. No. (4,441,502), this latter capability is determined by measuring with the NMR apparatus the ratio of the phosphocreatine (PCr) in the muscle to the inorganic phosphate (Pi) at different times during prescribed exercises. This latter ratio is a measure of the muscle efficiency.
Specifically described in this U.S. Pat. No. 4,441,502, is NMR equipment that includes a cylindrical electromagnet and a Cybex ergometer positioned adjacent to the electromagnet and having an oscillatable input lever within the bore of the electromagnet. A human subject places one of his arms within the bore of the electromagnet in a uniform field region thereof and grasps the oscillatable input lever, while the usual transceiver probe coil of the NMR equipment is maintained in proximity to the subject's wrist flexor muscle. The subject them oscillates the input lever by flexing his wrist at prescribed intervals through controlled strokes. Wristflexor muscle output is measured by the ergometer, while PCr and pi relationships are measured by the NMR apparatus.
Effective operation of the patented equipment depends upon the subject's carefully following prescribed instructions for the exercises. This being the case, it is difficult to utilize such equipment for evaluating the musculature of non-human animals, particularly untrained animals. Moreover, the patented equipment permits muscle evaluation only during the performance of relatively simple exercises, such as the above-described repetitive motion of the wrist of the subject.